Immunosuppressive drugs are used to inhibit or prevent the activity of the immune system for the treatment of certain diseases. Clinically, they are used to treat or prevent a number of conditions, for example, to prevent the rejection of transplanted organs and tissues (e.g. bone marrow, heart, kidney, liver etc.), and in the treatment of inflammatory diseases or autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, psoriasis, and inflammatory bowel disease. Immunosuppressive drugs currently approved for treatment of chronic inflammatory diseases need to be frequently administered, and carry significant side effects including risks of renal toxicity and morbidity.
Although immunosuppressive stromal cell types have been described (e.g. mesenchymal stromal cells), they are poorly defined, and have failed to meet primary efficacy endpoints in clinical trials. In addition, isolation of stromal cells remains challenging due to difficulties in successfully isolating these cells. Due to the severity and breath of conditions caused by unwanted immune activity, such as autoimmune or inflammatory diseases, there is a great need for developing effective treatments of such diseases.